Documentation: dt: interrupt-controller: fix spelling mistakes

Signed-off-by: NEric Engestrom <eric@engestrom.ch>
Signed-off-by: NRob Herring <robh@kernel.org>

Documentation/devicetree/bindings/interrupt-controller/ti,omap4-wugen-mpu

@@ -4,7 +4,7 @@ All TI OMAP4/5 (and their derivatives) an interrupt controller that
 routes interrupts to the GIC, and also serves as a wakeup source. It
 is also referred to as "WUGEN-MPU", hence the name of the binding.
 
-Reguired properties:
+Required properties:
 
 - compatible : should contain at least "ti,omap4-wugen-mpu" or
   "ti,omap5-wugen-mpu"
@@ -20,7 +20,7 @@ Notes:
 - Because this HW ultimately routes interrupts to the GIC, the
   interrupt specifier must be that of the GIC.
 - Only SPIs can use the WUGEN as an interrupt parent. SGIs and PPIs
-  are explicitly forbiden.
+  are explicitly forbidden.
 
 Example: